DE102019008766A1 - Temperature control device for cooling charge air for an internal combustion engine - Google Patents

Abstract

Temperature control device (1) with a refrigerant (M) leading circuit system (4) with two circuit parts (4.1, 4.2), wherein in a first circuit part (4.1) a first heat exchanger (5) through which the refrigerant (M) can flow, by means of which heat (Q) can be transferred between the refrigerant (M) and the charge air (L), is fluidically coupled on the input side to a conveying device (6) for conveying the refrigerant (M) and on the output side to a pressure side (7.1) of an ejector (7), in a second circuit part (4.2), connected fluidically parallel to the first circuit part (4.1), a second heat exchanger (8), by means of which heat (Q) can be transferred between the refrigerant (M) and the charge air (L), on the inlet side with an expansion valve (9) ) and is fluidically coupled on the outlet side to a suction side (7.2) of the ejector (7) and in the flow direction after an outlet of the ejector (7) a third heat exchanger (10) f through which the refrigerant (M) can flow is fluidly coupled to the ejector (7) and the circulatory system (4) is divided in the flow direction immediately after the third heat exchanger (10) at a branch (12) into the first circulatory part (4.1) and second circulatory part (4.2). According to the invention, the refrigerant (M) is 1,1,1,4,4,4-hexafluoro-2-butene or a Z-isomer of 1,1,1,4,4,4-hexafluoro-2-butene. There is also a method for operating such a temperature control device (1).

Description

The invention relates to a temperature control device for temperature control of charge air for an internal combustion engine according to the preamble of claim 1.

The invention further relates to a method for operating a temperature control device for temperature control of charge air for an internal combustion engine according to the preamble of claim 4.

From the DE 10 2016 013 926 A1 a cooling device for cooling charge air for an internal combustion engine with a circulation system carrying a cooling medium is known. The circulatory system has a first heat exchanger through which the cooling medium can flow and by means of which heat can be transferred between the cooling medium and the charge air. The circulatory system also has an ejector, by means of which the cooling medium can be subjected to a negative pressure. In addition, the circulatory system has a second heat exchanger through which the cooling medium can flow parallel to the first heat exchanger and by means of which heat can be transferred between the cooling medium and the charge air. The ejector is arranged in a fluid flow direction of the circulatory system behind the first heat exchanger and the second heat exchanger. The first heat exchanger is arranged in a first circuit part of the circuit system together with a conveying device for conveying the cooling medium, the first circuit part opening into a pressure side of the ejector. The second heat exchanger is arranged together with an expansion valve in a second circuit part of the circuit system, the second circuit part opening into a suction side of the ejector. When the conveying device is operated to convey the cooling medium through the circulatory system, the interaction of the expansion valve and the ejector results in a lower fluid pressure of the cooling medium in the second circulatory part than in the first circulatory part.

The invention is based on the object of specifying a temperature control device for controlling the temperature of charge air for an internal combustion engine, which is improved over the prior art, and an improved method for operating such a temperature control device.

The object is achieved according to the invention by a temperature control device which has the features specified in claim 1 and by a method which has the features specified in claim 4.

Advantageous refinements of the invention are the subject of the subclaims.

A temperature control device for temperature control of charge air for an internal combustion engine comprises a circulation system which carries a refrigerant and has two circulation parts. In a first circuit part, a first heat exchanger through which the refrigerant can flow, by means of which heat can be transferred between the refrigerant and the charge air, is fluidically coupled on the inlet side to a conveying device for conveying the refrigerant and on the outlet side to a pressure side of an ejector. In a second circuit part, connected fluidically parallel to the first circuit part, a second heat exchanger, by means of which heat can be transferred between the refrigerant and the charge air, is fluidically coupled on the inlet side to an expansion valve and on the outlet side to a suction side of the ejector. In the direction of flow after an outlet of the ejector, a third heat exchanger through which the refrigerant can flow is fluidly coupled to the ejector and the circuit system is divided into the first circuit part and the second circuit part in the flow direction immediately after the third heat exchanger at a junction.

According to the invention, the refrigerant is 1,1,1,4,4,4-hexafluoro-2-butene, R1336mzz for short, or a Z-isomer of 1,1,1,4,4,4-hexafluoro-2-butene, for short R1336mzz-Z.

A so-called stand-alone refrigerant circuit is implemented by means of the temperature control device, by means of which the temperature control of the charge air is decoupled from an ambient temperature. Furthermore, the temperature control device is particularly efficient due to the use of the ejector, since the ejector uses the heat to be removed from the charge air as a drive source. As a stand-alone refrigerant circuit, the temperature control device is designed to ensure adequate cooling of the charge air, regardless of the ambient temperature and engine operation.

The refrigerant, which is formed as 1,1,1,4,4,4-hexafluoro-2-butene or Z-isomer of 1,1,1,4,4,4-hexafluoro-2-butene, differs from other cooling media, in particular from 2,3,3,3-tetrafluoropropene, or R1234yf for short, has a lower global warming potential (GWP), so that the greenhouse effect is reduced. Furthermore, the refrigerant has a particularly high safety class (A1) and a particularly high thermal stability of up to 250 ° C. and requires a lower drive power of the delivery device. This on the one hand increases the useful power of the internal combustion engine and on the other hand makes an important contribution to climate protection. Furthermore, requirements according to the emissions in practical driving operation, also known as Real Driving Emissions, RDE for short, are met.

Embodiments of the invention are explained in more detail below with reference to drawings.

• 1 schematisch ein Schaltbild eines ersten Ausführungsbeispiels einer Temperiervorrichtung zum Temperieren von Ladeluft für eine Verbrennungskraftmaschine,
• 2 schematisch ein Schaltbild eines zweiten Ausführungsbeispiels einer Temperiervorrichtung zum Temperieren von Ladeluft für eine Verbrennungskraftmaschine,
• 3 schematisch eine hydraulische Leistung einer Fördervorrichtung einer Temperiervorrichtung in Abhängigkeit eines Verhältnisses eines Hochtemperatur-Massenstromes zu einem Gesamtmassenstrom verschiedener Kältemittel und
• 4 schematisch einen Wirkungsgrad eines Ejektors einer Temperiervorrichtung in Abhängigkeit eines Verhältnisses eines Hochtemperatur-Massenstromes zu einem Gesamtmassenstrom verschiedener Kältemittel.

Show:

• 1 schematically a circuit diagram of a first embodiment of a temperature control device for temperature control of charge air for an internal combustion engine,
• 2 schematically a circuit diagram of a second embodiment of a temperature control device for temperature control of charge air for an internal combustion engine,
• 3 schematically a hydraulic power of a conveying device of a temperature control device as a function of a ratio of a high temperature mass flow to a total mass flow of various refrigerants and
• 4th schematically an efficiency of an ejector of a temperature control device as a function of a ratio of a high-temperature mass flow to a total mass flow of various refrigerants.

Corresponding parts are provided with the same reference symbols in all figures.

In 1 is a circuit diagram of a possible embodiment of a temperature control device 1 for temperature control of charge air L. a turbocharger 2 for an internal combustion engine 3 shown.

It is known that to increase the efficiency of internal combustion engines 3 Parts of an exhaust energy via the turbocharger 2 to be recovered. With this power, air is generated before it enters the internal combustion engine 3 , ie the charge air L. , pre-compressed, whereby the density of the air increases and with the same volume a combustion chamber of the internal combustion engine 3 more oxygen can be supplied. Thus, a cubic capacity of the internal combustion engine 3 can be reduced at the same or higher power, whereby fuel consumption can be reduced. During the compression of the air, however, it heats up strongly and a charge air density drops, as a result of which less fuel enters a combustion chamber of the internal combustion engine 3 can be injected and this can accordingly only provide a lower output. Furthermore, the increased charge air temperature increases the exhaust gas temperature and the risk of knocking in gasoline engines. To ensure optimal combustion in the internal combustion engine 3 ensure to avoid knocking in gasoline engines and a temperature after the internal combustion engine 3 For reasons of component protection, the compressed charge air is restricted L. by means of the temperature control device 1 before entering the internal combustion engine 3 tempered, especially cooled.

The temperature control device 1 includes a refrigerant M. leading circulatory system 4th with two circuit parts 4.1 , 4.2 . The refrigerant M. is 1,1,1,4,4,4-hexafluoro-2-butene or a Z-isomer of 1,1,1,4,4,4-hexafluoro-2-butene.

In a first part of the cycle 4.1 is one with the refrigerant M. flowed through first heat exchanger 5 intended. By means of the first heat exchanger 5 , for example a high temperature heat exchanger or high temperature evaporator, there is heat Q between the refrigerant M. and the charge air L. transferable. Here is the first heat exchanger 5 on the input side with a conveyor 6th for conveying the refrigerant M. , for example a feed pump or a compressor, and on the output side with a pressure side 7.1 an ejector 7th fluidically coupled.

In a fluidically parallel to the first part of the circuit 4.1 switched second part of the circuit 4.2 is a second heat exchanger 8th intended. By means of the second heat exchanger 8th , for example a low-temperature heat exchanger or low-temperature evaporator, there is heat Q between the refrigerant M. and the charge air L. transferable. Here is the second heat exchanger 8th On the inlet side with an expansion valve 9 and indirectly with a suction side on the outlet side 7.2 of the ejector 7th fluidically coupled.

That is, the first part of the cycle 4.1 and the second circuit part 4.2 open on the pressure side 7.1 or the suction side 7.2 of the ejector 7th in these and are thus connected to one another at this. Downstream of the ejector 7th are the two parts of the cycle 4.1 , 4.2 separated again.

This is where the ejector 7th operated for example according to a so-called Venturi principle, so that in the first part of the circuit 4.1 a greater fluid pressure of the refrigerant M. prevails than in the second part of the cycle 4.2 . Thus, in the second heat exchanger 8th the refrigerant M. out at a lower pressure than in the first heat exchanger 5 . Due to the lower pressure, the refrigerant can M. in the second part of the cycle 4.2 and thus in the second heat exchanger 8th compared to the first heat exchanger 5 are more easily evaporated and have a lower temperature level. This provides a particularly efficient, step-by-step cooling of the charge air L. and thus a particularly efficient operation of the internal combustion engine 3 enables.

There is also the second heat exchanger 8th on the output side with a heat emission side 11.1 an integrated heat exchanger 11 fluidically coupled and the conveying device 6th is on the inlet side with a heat absorption side 11.2 of the integrated heat exchanger 11 fluidically coupled. In one possible embodiment, the integrated heat exchanger is omitted 11 .

In one operation of the temperature control device 1 occurs from the turbocharger 2 compressed charge air L. in the first heat exchanger 5 one and is cooled there before it is in the internal combustion engine 3 is fed. The refrigerant M. is in a further heat exchanger designed in particular as a condenser 10 those of the charge air L. absorbed heat Q is withdrawn and given off, for example, to the ambient air.

After exiting the further heat exchanger 10 divides the circulatory system 4th at a junction 12th , which is designed, for example, as a control valve, into the two circuit parts 4.1 , 4.2 on. The branch designed as a control valve regulates the process 12th a mass flow distribution between the first circuit part 4.1 and the second circuit part 4.2 .

In the first part of the cycle 4.1 becomes part of the refrigerant M. by means of the heat absorption side 11.2 of the integrated heat exchanger 11 If this is present, cooled further and then by means of the conveyor device 6th to the first heat exchanger 5 promoted. Through the conveyor 6th experiences the refrigerant M. an increase in pressure compared to the additional heat exchanger 10 . In the first heat exchanger 5 takes the refrigerant M. the heat Q from the charge air L. on before it continues as a propellant mass flow to the ejector 7th flows. The charge air L. is determined by its maximum temperature when entering the first heat exchanger 5 cooled to a medium temperature level.

The charge air flows from there L. further into the second heat exchanger 8th the remaining heat Q of the charge air to be dissipated L. to that in the second part of the cycle 4.2 guided refrigerants M. gives away. This can result in a relaxation of the refrigerant M. take place at temperatures below the ambient temperature. After the second part of the cycle 4.2 becomes the refrigerant M. in the direction of flow after the further heat exchanger 10 based on a pressure drop in the expansion valve, which can in particular be regulated 9 to a lower pressure and temperature level than on the third heat exchanger 10 relaxed. Then the refrigerant occurs M. into the second heat exchanger 8th and withdraws the charge air L. additional heat Q. After that, the refrigerant M. by means of the heat emission side 11.1 of the integrated heat exchanger 11 If this is available, it is further heated, in particular overheated, by the ejector 7th sucked in and reunites with the refrigerant M. of the first part of the circulatory system 4.1 . A temperature level in the second heat exchanger 8th is via a throttling effect of the expansion valve 9 adjustable.

This control includes the expansion valve 9 a control unit 9.1 , which, for example, with at least one, in the flow direction immediately after an exit of the heat release side 11.1 of the integrated heat exchanger 11 arranged, not shown temperature sensor is data-coupled. The temperature of the superheated refrigerant is determined based on signals from the temperature sensor M. in the direction of flow after the exit of the heat release side 11.1 determined. Depending on this temperature, its setpoint is a controlled variable for the expansion valve 9 the expansion valve is regulated 9 . This regulation takes place electrically and / or thermally, whereby it can be ensured by means of the regulation that the refrigerant M. in the integrated heat exchanger 11 completely overheated.

An achievable mass flow in combination with a desired temperature level is achieved via an adjustable suction power of the ejector 7th set. This forms the first part of the cycle 4.1 guided refrigerants M. after the first heat exchanger 5 a propellant mass flow and is used by coupling with the pressure side 7.1 of the ejector 7th as the drive source of the same. Depending on a state of the refrigerant M. , for example as wet steam or superheated gas, a mass flow and an absorbed heat Q, there is a suction power of the ejector 7th a. The propellant mass flow is in a propulsion nozzle, not shown in detail, of the ejector 7th relaxes and enters the ejector at the speed of sound, for example 7th a. When it emerges from the propellant nozzle, a negative pressure is created, which creates a mass flow of the refrigerant M. from the second heat exchanger 8th of the second part of the circuit 4.2 sucks in and therefore works as a jet pump. In the ejector 7th combine the propellant mass flow and the sucked in mass flow of the refrigerant M. and are before exiting the ejector 7th slowed down and relaxed to a desired pressure level. Here is the ejector 7th executed with a static geometry or controllable. An adjustable ejector 7th acts as a further manipulated variable to regulate the cooling capacity of the temperature control device 1 .

In particular at low ambient temperatures and / or when the internal combustion engine is in operation 3 in the so-called partial load range there is no cooling of the charge air L. with the maximum possible cooling capacity of the cooling circuit required and only a relatively small amount of heat Q from the heat exchangers 5 , 8th on the refrigerant M. transfer. Due to the reduced amount of heat to be dissipated, the efficiency of the ejector decreases 7th so that one from the conveyor 6th Delivery rate to be applied to generate a pressure increase on the ejector 7th and thus the energy consumption of the conveyor 6th climb.

To avoid this, one is the ejector 7th immediate, by means of a switching unit 13th , for example a switching valve, switchable bypass line 14th provided, which on the input side with an output of the first heat exchanger 5 and on the output side via the third heat exchanger 10 with an input of the conveyor device 6th and the inlet of the expansion valve 9 is fluidically coupled.

This bypass line 14th is exceeded by means of the cooling device when a predetermined limit value is exceeded 1 to be generated cooling power deactivated, so that the refrigerant M. in the first part of the circulatory system 4.1 from the exit of the ejector 7th via the third heat exchanger 10 and the conveyor 6th to the first heat exchanger 5 and from this over the print side 7.1 of the ejector 7th to whose exit is led. In the second part of the cycle 4.2 becomes the refrigerant M. from the exit of the ejector 7th via the expansion valve 9 to the second heat exchanger 8th and from this via the suction side 7.2 of the ejector 7th led to its exit.

When falling below a predetermined limit value by means of the cooling device 1 The bypass line becomes the cooling power to be generated 14th on the other hand activated so that the refrigerant M. from the output of the bypass line 14th via the third heat exchanger 10 and the conveyor 6th to the first heat exchanger 5 and from this to the inlet of the bypass line 14th to be led. Thus, only the first heat exchanger 5 and the third heat exchanger 10 operated, whereas the second part of the circuit 4.2 via the expansion valve 9 due to a lack of suction power of the ejector 7th is switched off. The conveyor device must 6th no pressure increase at the ejector 7th , but only a pure volume transport of the refrigerant M. within the first part of the circulatory system 4.1 produce.

2 shows a circuit diagram of a second exemplary embodiment of a temperature control device 1 for temperature control of charge air L. for an internal combustion engine 3 .

In contrast to the in 1 The illustrated embodiment includes the temperature control device 1 one to the third heat exchanger 10 downstream fourth heat exchanger 15th , which is designed as a low-temperature cooler to carry out what is known as subcooling. By means of the fourth heat exchanger 15th becomes the temperature of the refrigerant M. which is 1,1,1,4,4,4-hexafluoro-2-butene or a Z-isomer of 1,1,1,4,4,4-hexafluoro-2-butene, before entering the first Heat exchanger 5 further lowered, so that there is a higher temperature gradient between the refrigerant M. in the second part of the cycle 4.2 and the charge air L. in the second heat exchanger 8th adjusts. An improved heat extraction can thus be realized.

In 3 is a hydraulic power P of the delivery device 6th a temperature control device 1 as a function of a ratio of a high-temperature mass flow m1 to a total mass flow m2 of the refrigerant M. , which is 1,1,1,4,4,4-hexafluoro-2-butene or a Z-isomer of 1,1,1,4,4,4-hexafluoro-2-butene, compared to several other refrigerants M2 to M7. This means, 3 shows the hydraulic power P of the conveyor 6th with different refrigerants M. , M2 to M7 with regard to a mass flow distribution between high-temperature and low-temperature paths of the circulatory system 4th . 4th shows an efficiency η of an ejector 7th a temperature control device 1 depending on the ratio of a high-temperature mass flow m1 to the total mass flow m2 for the refrigerants M. , M2 to M7.

Here is the refrigerant M2 2,3,3,3-tetrafluoropropene, or R1234yf for short, is the refrigerant M3 a mixture of dimethyl ether and ammonia, or R723 for short, at 42 bar pressure, the refrigerant M4 isobutane, the refrigerant M5 trans-1,3,3,3-tetrafluoroprop-1-ene, or R1234ze for short, the refrigerant M6 1-chloro-3 , 3,3-trifluoropropene, R1233zD for short, and the M7 refrigerant is a mixture of dimethyl ether and ammonia, R723 for short.

In the 4th shown low-lying curves of the refrigerants M. and M6 indicate an existing potential for a reduction in performance with a better adaptation of the operational framework conditions. Thus the curves shift accordingly 3 downwards when the curves are raised in accordance with 4th . This enables a drive power of the conveying device to be reduced 6th by improving the efficiency η of the ejector 7th .

When considering a realistically achievable degree of efficiency η of the ejector 7th (η = 30% are assumed to be the maximum achievable) indicate the refrigerant M. and the refrigerant M6 has a lower hydraulic power P compared to the other refrigerants M2 to M5, M6, M7. The refrigerant M4 is to be regarded as very critical due to its high flammability and also requires a significantly higher hydraulic power P compared to the refrigerants M. , M6. The refrigerant M3 Despite a significant pressure increase of up to 42 bar, there is no significant advantage over refrigerants M. and M6.

From this point of view, the refrigerants are suitable M. and M6 for use of the 1 and 2 illustrated embodiments of the temperature control device 1 , whereby the refrigerant M6 is not suitable for charge air cooling at a charge air temperature of up to approx. 200 ° C due to a maximum operating temperature of 175 ° C. So the refrigerant is M. , which is 1,1,1,4,4,4-hexafluoro-2-butene or a Z-isomer of 1,1,1,4,4,4-hexafluoro-2-butene, particularly advantageous for use in the illustrated embodiments of the temperature control device 1 .

List of reference symbols

1

Temperature control device

2

turbocharger

3

Internal combustion engine

4th

Circulatory system

4.1

Circulatory part

4.2

Circulatory part

5

Heat exchanger

6th

Conveyor

7th

Ejector

7.1

Print side

7.2

Suction side

8th

Heat exchanger

9

Expansion valve

9.1

Control unit

10

Heat exchanger

11

integrated heat exchanger

11.1

Heat release side

11.2

Heat absorption side

12th

Junction

13th

Switching unit

14th

Bypass line

15th

Heat exchanger

L.

Charge air

M.

Refrigerant

M2

Refrigerant

M3

Refrigerant

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102016013926 A1 [0003]

Claims (4)

Temperature control device (1) for controlling the temperature of charge air (L) for an internal combustion engine (3) with a refrigerant (M) leading circuit system (4) with two circuit parts (4.1, 4.2), wherein - in a first circuit part (4.1) one with the First heat exchanger (5) through which refrigerant (M) can flow and by means of which heat (Q) can be transferred between the refrigerant (M) and the charge air (L), on the inlet side with a conveying device (6) for conveying the refrigerant (M) and on the outlet side with a The pressure side (7.1) of an ejector (7) is fluidically coupled, - in a second circuit part (4.2) connected fluidically parallel to the first circuit part (4.1), a second heat exchanger (8), by means of which heat (Q) between the refrigerant (M) and the charge air (L) can be transmitted, is fluidically coupled on the inlet side to an expansion valve (9) and on the outlet side to a suction side (7.2) of the ejector (7) and - in the flow direction to an outlet of the ejector s (7) a third heat exchanger (10) through which the refrigerant (M) can flow is fluidically coupled to the ejector (7) and the circulatory system (4) in the flow direction immediately after the third heat exchanger (10) at a junction (12) in divides the first circuit part (4.1) and second circuit part (4.2), characterized in that the refrigerant (M) 1,1,1,4,4,4-hexafluoro-2-butene or a Z-isomer of 1.1, Is 1,4,4,4-hexafluoro-2-butene. Temperature control device (1) according to Claim 1 , characterized in that - between the branch (12) and an inlet of the conveyor device (6) a heat absorption side (11.2) of an integrated heat exchanger (11) is fluidically coupled to the first circuit part (4.1) and / or - between the branch (12 ) and an input of the expansion valve (9), the heat absorption side (11.2) of the integrated heat exchanger (11) is fluidically coupled to the second circuit part (4.2). Temperature control device (1) according to Claim 1 or 2 , characterized by a switchable bypass line (14) bypassing the ejector (7), which is fluidically coupled on the inlet side to an outlet of the first heat exchanger (5) and on the outlet side at least indirectly to an inlet of the conveying device (6) and an inlet of the expansion valve (9) . Method for operating a temperature control device (1) for controlling the temperature of charge air (L) for an internal combustion engine (3) with a circulation system (4) carrying a refrigerant (M) with two circulation parts (4.1, 4.2), wherein - in a first circulation part (4.1 ) a first heat exchanger (5) through which the refrigerant (M) can flow, by means of which heat (Q) is transferred between the refrigerant (M) and the charge air (L), on the input side with a conveying device (6) for conveying the refrigerant (M) and is fluidically coupled on the output side to a pressure side (7.1) of an ejector (7), - in a second circuit part (4.2) connected fluidically parallel to the first circuit part (4.1), a second heat exchanger (8), by means of which heat (Q) between the Refrigerant (M) and the charge air (L) can be transferred, is fluidically coupled on the inlet side with an expansion valve (9) and on the outlet side with a suction side (7.2) of the ejector (7) and - in the direction of flow after an outlet of the ejector (7), a third heat exchanger (10) through which the refrigerant (M) can flow is fluidly coupled to the ejector (7) and the circulatory system (4) is at a junction immediately after the third heat exchanger (10) in the direction of flow (12) divided into the first circuit part (4.1) and second circuit part (4.2), characterized in that the refrigerant (M) 1,1,1,4,4,4-hexafluoro-2-butene or a Z-isomer of 1,1,1,4,4,4-hexafluoro-2-butene is used.

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